Motorized pulley



Oct. 28, 1952 D. A. scHRocK 2,615,941

MOTORIZED PULLEY Filed Jan. 9, 1951 s sheets-sheet 1 Il. w. w m w j W lwjmmkl MJ M wm. Nm. wm. J f r 5 Z i mw. (Aw. w W l i l D wi ww. 1 ,wvl l w .!ll mm L UrwlwlM um. -Il ww mm. l l! HIHUWHI will u I i J i wm w NN ST |11. Nb ,w www@ m/w Q 3 WMM rl ,QW H TIJLHI. @u ww Q ww v ,ww mw l :iii .uw QN hw Oct. 28, 1952 D, A SCHROCK 2,615,941

MOTORIZED PULLEY Filed Jan. 9, 1951 3 sheets-sheet 2 Oct. 28, 1952 o. A. scHRocK 2,615,941

MOTORIZED PULLEY Filed Jan. 9, 1951 5 Sheets-Sheet 3 ff if y 'LA' @MMW Patented Oct. 28, 1952 UNITED STATES PATENT OFFICE MOTORIZED PULLEY Daniel A. Schi-ook, Boise, Idaho, assigner to Idaho Sprocket and Machine Works, Boise, Ida-ho, a cia-'partnership Application January V9, 1951, Seria'l'o. 205,064

(CllZ-e-SS) 3 Claims. 1

This invention relates to motorized pulleys and deals particularly with improvements rendering such pulleys practicable for extremely heavy duty equipment. 'More specifically, it discloses a motorized pulley cf simpliied construction yet of unusual strength and rigidity, so that it is suitable for use as a head pulley for heavy duty conveyor systems, particularly conveyor belts employed in handling materials such as coal, rock or mineral ores.

It is common knowledge that there have been in the prior art many proposals to provide .pulleys, hoisting drums and the like with a selicontained driving motor, but it is equally well known that the structures which have been proposed for this purpose in Vthe past have been subject to certain rather well defined limitations, With the result that equip-ment oi this kind heretofore devised has not vheretofore shown itself to be practicable for extremely heavy duty applications wherein the pulleys (and the frames and bearings on which they are mounted) are subjected to the loads, shocks, impacts and eirtremestresses encountered in material handling equipment.

There appear to be several underlying reasons for this. For one thing, the motorized pulleys heretofore developed have'been in most case quite vcomplex and delicate and, in some instances, at least "have been so designed that the extreme lateral strains or shocks imposed on the pulley drum by the tension of the belt and by the periodic impacts of large rocks striking the pulley surface could be transmitted to the motor ory speed reducer housings or shafts, or to other equally delicate parts of the unit. Notwithstanding this, most motorized pulleys of the prior art are so designed that they are expensive to manufacture, While at the same time are so assembled as to be ditcult to repair or service. It also appears that their design and construction has more often .than not been such as to require the use of external collector rings andbrushes to energize the internal motor. This obviously renders such a pulley nearly 'useless for material handling purposes Where such delicate exterior parts Would not only soon be' ruined by dust and grit vbut would be entremely subject to breakage due t'o falling pieces of rock', ore, etc.

Aln other designs of the equipment, the parts have been so related as to present very didicult problems in construction and in maintaining proper alignment of Athe parts. Another factor (of possibly even greater practical importance in connection with heavylduty equip'- ment) arises from the fact that the motorized pulleys heretofore devised, at least insofar `as known to this applicant, have been of such design and Vconstruction that they require bearings or bearing mountings of special design'or construction, or that they requirespecial reinL forcements or strengthening of ltheir mounting frames in 'order to function in a satisfactory manner. Obviously'such equipment is vv'a'luelss from a commercial standpoint since to be ac-` ceptable to the trade it'I is essential that Iany proposed motorized pulley be quickly inter-N changeable With ordinary conventional "pulley drums, Without further 'modifications'of 'the 'com veyor.

The net result has been that While the obvious advantages of providing a motorized headpulley for a material handling conveyor, for example, have been fully recognized, it has nevertheless been a rather impractical expedient with mo torizecl units of the types heretofore devised. The result is that in the present commercial development of the art the pulleys employed in material handling conveyors are in almost all instances of conventional construction, powered by an exterior motor and speed reducer.

It is the general aim of the present invention to provide a motorized Vheadpulley for a heavy duty kmaterial handling 'conveyor wherein the several coactingparts of the pulley are so re-y lated to each other as to achieve all of the ad-V vantages inherent in a motorized pulley, .yet to do this Without incurring the disadvantage'ous features of motorized pulleys of rthe types 'here-u tofore proposed. This involves several aspects. For `one thing, it involves the provision o'f a motorized pulley so designed and constructed that vit may be satisfactorily mounted in conventional bearings or pillow blocks' ofthe same identical type and constructionas'are'ordinarily used with equipment having pulley Adrum-s and axles of the conventional type.

In addition to this, it is essential that the motorized pulley be" of 'such design thatitdoe's not lin'ipose any torque' `iorcesjo'n the Vvbeariirig structures Whichcarry it, and does lnot bringV about any twisting strains whichmight tend to ilex the frames on Awhich the bearings'- 'are mounted or cause misalign'ment of the 'bearings under severe conditions of loading or Vat 'the instant of violent impact. In this connection, it may be well to explain that in h'e'ayy duty material handling equipment, the necessity yfor maintaining a reasonable Weight the conveyor' frames prevents the use of any bracing not absolutely necessary for satisfactory operation. t follows that to be satisfactory for its purpose, a motorized pulley must be ci such design and construction that it maintains all of the characteristics of rigidity inherent in a simple drum and axle, and thus achieves its purpose without imposing any twisting strains on its bearings or on the frames by which the bearings are carried.

lt is a further object of the invention to provide a motorized pulley wherein the driving mechanism (that is, the motor, speed reducer and related parts), are of such construction and so related to the other parts of the pulley that these parts are not at any time subject to any lateral load such as may be imposed on the pulley by the tension of the conveyor belt or by the shock of impact of large rocks, etc. striking the pulley drum. By this expedient the relatively delicate castings characteristic of most commercial motors are protected against breakage, and the rotary parts of the motor and speed reducer are relieved of any7 stresses which might otherwise cause deviations from ^erfect alignment and thus bring about unnecessary friction and wear in the various operating parts of the unit. This makes it entirely practicable to drive the unit by a motor of conventional design, and

eliminates any need of a special motor or special motor housing, as are often required by motorized pulleys of prior types.

A still further object of the invention is the provision of a driving unit for a motorized pulley wherein the driving unit consists of a speed reducer and an electric motor coupled to each other by a relatively small threaded sleeve, so that the motor is supported wholly on the speed reducer, but may be isolated therefrom by an oil Seal and baffle or bulkhead within the pulley drum, with the result that the entire driving unit may be sup-ported at two points only, so that it is to a certain extent self-aligning and not unduly affected by minor inaccuracies of alignment.

In short, the present invention proposes to provide a motorized pulley wherein the pulley drum, end plates and journals operate as a Single rigid unitary external frame, and thus function as the equivalent of a conventional drum l and axle in the sense that these parts support the entire lateral load imposed upon the pulley and are the only parts subjected to the shock of any impact against the drum surface. The driving unit, on the other hand, is so designed and l so related to the pulley drum that it is subjected to no lateral load whatsoever, but carries only the torque load of the pulley. In short, this invention proposes to provide a motorized pulley wherein the exterior drum, end plates and journals pack the load as far as lateral strains are concerned, and thus leave the driving unit free to develop the torque required without any lateral stresses which might tend to cause breakage, increase friction, or cause undesirable deviail tions from proper alignment which would bring about excessive wear.

The foregoing objects are accomplished in the present invention by the provision of a motorized pulley wherein the pulley drum, end plates and journals are permanently bolted together so that they function as a single integral piece and thus have adequate rigidity to maintain the journals in perfect alignment, even under the many extreme and variable lateral loads to which they are subjected. With such a construction, these loads are applied to the bearings in a lateral direction only and without any twisting moments of force. The driving unit of the pulley is mounted within this drum, but forms no part of the supporting structure thereof, so that it is subjected to torque loads only.

A preferred embodiment of the invention is illustrated in the drawings of this specification, wherein:

Figure l is a longitudinal sectional View through a head pulley of the type contemplated herein;

Figure 2 is a detail view of a hydraulic cylinder associated with the torque arm of the pulley to provide a weighing device for the material being handled in the conveyor belt, the view being taken substantially on the plane of the line 2-2 of Figure l;

Figure 3 is an exploded view of the pulley assembly shown in Figure l;

Figure i is a detail cross sectional View of the frame or load carrying structure of the pulley, with the driving unit removed;

Figure 5 is a side elevation of the driving unit; and

Figure 5 is a detail sectional View through the speed reducing section of the driving uni-t, the view being taken on the plane of the line il-E of Figure 5.

The pulley comprises a cylindrical drum il] having end plates il and l2 in which hub portions ii and ll are mounted. The hub portions have outwardly extending aligned stub shafts or journals l5 and l@ integral therewith. The end plate i l consists of a pair of circular discs ll' and it welded to each other and welded to the hub i3, with the outer periphery of the disc il removably bolted to a ring l il welded on the inside of the drum l@ adjacent the left end thereof. The disc Il carries a ring gear 2l and centering lugs 22, so that the entire end assembly functions as a single rigid, unitary plate. Similarly, the end plate I2 consists of an inside disc 23 bolted to the ring 2d on the drum iii with a central reinforcing disc 25 to add rigidity to the structure. Thus, when the parts are assembled, the drum, end plates and journals function as a unit-ary frame which is extremely rigid and which provide a pulley which may be mounted in any conventional bearings or pillow blocks, such as represented by the bearings 2t and El.

The manner in which these frame parts are assembled and mounted is best illustrated in Figure 4, from which it will be seen that the parts thus described provide a complete pulley adapted to mounting in conventional bearings, and designed to adequately support any lateral loads such as might be imposed upon it by the strain of the conveyor belt.

The driving unit of the device is an entirely separate mechanism as illustrated in Figure 5. This unit consists of a speed reducer having a frame composed of end plates 3l and 32 joined by a plurality of integral posts 33 extending therebetween. The end plate 32 carries a fixed sleeve 'all which projects therefrom, and has a threaded end portion on which the supporting plate 35 of an electric motor 36 may be mounted. The opposite end plate 3i of the frame has a central hub 3l' in which a torque shaft 38 is mounted, with the torque shaft projecting to the left as viewed in the drawings.

Thus, from Figure 5 of the drawings it will be apparent that the driving unit of the device is a self-"containedmechanism wheremtiiearmature shaft 4I'T of the motor' extends throughk an oil' sealV 42rand bearing 43, so' that thev pinion 44 (which may be formed asfan integral part of the shaft 4i may project beyond theplatef32`of the about rotation of the'drum I0.

Theinterior of thed' rum I0 is divided intc'ranV oil housingl and a motorz compartment 52 by an interior plateor bulkhead 53, .which is welded in' position' at Aan intermediatev point between'the` end platesll and l2. The motor'comp'artment 52 ispreferably provided with anumberofaper-ltures 54 to provide adequate' ventilation for the motor-wand as'illustrated, the motor is provided with 'a semi-circular hood 55`secured to the sup'- porting plate thereof to shield' the armature shaft from any foreign'V substances that might enter the motoncompartment through the ventilating openings. drum may be provided with a removable i'lller and drain plug 56 as indicated.-

The driving unit of the device is supported primarilyon a center bearing 51 in the' bulkhead 53, and it will be seen from Figures-l'fand' that this bearingjsurrounds the sleeve'S and'supports the speedreducing unit insuch a manner that theY torque shaft 38 thereof may project outwardlythrough the hollow journal l5? and through the hubV 5S to a torque arm 59' which serves to restrain the driving unit against rota'- tion within the drum. The shaft is connected to the arm by a coil spring 6I anchored to the shaft at G2 and secured to the arm by the cap screw 53 so as to cushion any torque stresses.

In the form of the invention illustrated, the

torque arm 59 has its lower end portion arranged to bear against a plunger 54 (Figure 2), which is provided with a reduced piston portion B5 slidable in a hydraulic cylinder Se and having oil seals 67 therein. The interior of the cylinder S6 has a port 58 communicating with a conventional pressure gauge 69 which registers the pressure imposed on oil within the cylinder by the torque arm 59. Thus, the dial of the pressure gauge 5S may be calibrated to register the weight of the material being brought up the conveyor belt, so that the gauge will not only give an indication of any dangerous overloading which might occur, but will also function as a constant weighing device whereby the weight of material handled on the conveyor may be determined. An anti-friction bearing Si.) is preferably provided within the hub i3 as shown, and oil seals 8i and 82 are provided at the outer end of the journal i5 and at the center bearing E? of the bulkhead 52 respectively, so that the entire speed reducing unit is suspended in an oil bath, and secured between the bearings 51 and 5o. The motor 3B is mounted in outboard relationship to the speed reducing unit and supported wholly upon the sleeve 34 thereof, but is in a separate ventilated compartment of the drum. It is, however, held against rotation by the threaded connection with the sleeve 34, which tightens in response to motor torque. Thus, the motor may conveniently be energized by electrical leads il extending outwardly through the hollow hub and journal IB at the right hand end of the device and, as

` Thus, when the motor is ener-- gized, the gears 44, and 41 areldriven to bring The oil housing' 5l o f the shown; these zlea'dsf maybe-closed: within sista;-

From'zth'e above it'will beiapparentthat; sirice'ey theimotor housing'. des notrotate; thezlusezof collector. rings." andi.r brushes f. outside.. ofth'e drum is `entirelyunnecessary.V Moreover; .it"is'to'.be.ob\

served.: that motorized pulleys of this.;` design L dofV noti impose any torque forceson the bearing.: structures'. which carry.` them,` and dor not bring.; about"` any twisting. strains which mightte'ndl to* dei; vthe .frames on which 'the bearings' `are .mountied. It follows that these pulley'shcann'ot--tend to" cause misalignment of their. bearings even under the most severe? conditions of. loading, .and that'.` theyi are:y therefore of such designv and' con-rv struction that vthey? requirernospecial lbearingsron mountings, `but mayl be vjournaledy in bearingsA of conventional. construction,` without"v special reinr forcementsY` or strengthening of:v the` bearings-1.

tliemselvesor of theirmountingl frames;

The internal driving vmechanisms 'of the pulleys are. of such construction andso relatedY tork the: other parts of thepulley that they are :subject to4 torque' loads only, and are'not atY any. timesubject toa'nyishockor lateral loa'dsuch asmayfb'eim-y posed: on the pulley by they tension of :thecon-fveyor' belt i' thereon; This largely eliminates the;A

cause of most alignment difcultiesra-ndiavoids? unnecessary friction; thus? reducing:wearrinutlief operatingp'arts o'flthe'u'n'it'.v

Tnet motor'f of' the driving.' unit. is. supported?.

wholly onthe speedr reducerby 'az relativelysniall threaded sleeve', `so that" these" sections off' the .f drivingunit may'beisolatedfby an oil seal arid` bai'e within thefpulley drum", yet Iso that the-eri@- tired'rivingunit may be supportedat'two'pointsf` only, and well balanced on its supports. lWith this arrangement these parts are to a certain extent self-aligning and not unduly affected by minor inaccuracies of alignment of the coacting parts of the pulley drum or journals, which has often been extremely troublesome in units of prior art design.

In conclusion, it is submitted that the present invention provides a motorized pulley wherein the pulley drum, end plates and journals operate as a single rigid unitary structure, and thus function as the equivalent of a conventional drum and axle in that these parts support the entire lateral load imposed upon the pulley, while the driving unit is subject to no lateral load whatsoever, but carries onlythe torque load to which the pulley is subjected. rihus the frame of the pulley packs the load so to speak, and leaves the driving unit free of unnecessary friction and capable of developing the high degree of torque required in heavy duty equipment.

Having thus described my invention, what I claim as new and desire to secure by United States Letters Patent is:

l. In a motorized pulley of the type having an exterior rotatable drum and a stationary driving motor housed therein, means for relieving the motor shaft from lateral loads imposed upon the drum comprising, in combination, a pair of end plates each rigidly secured to the drum and having a central hub therein, with hollow stub shafts xed on the end plates and projecting outwardly from the hubs thereof; together with a free floating driving unit within said drum and a transverse bulkhead between the end plates of the drum supporting said driving unit; the driving unit comprising a speed reducer having a frame consisting of a pair of end plates carrying asiatici shafts, and said motor and speed reducer are self--v aligning and wholly free of lateral strains.

'2. 1n a motorized pulley of the type having an exterior rotatable drum and a stationary driving motor housed therein, means for relieving the motor shaft from lateral loads imposed upon the drum comprising, in combination, a pair of end plates each rigidly secured to the drum and having a central hub therein, with hollow stub shafts xed on the end plates and projecting outwardly from the hubs thereof; together with a free heatn ing driving unit within said drum and a transverse bulkhead between the end plates of the drum supporting said driving unit; the driving unit comprising a speed reducer having a frame carrying a torque shaft and motor mounting sleeve respectively, the said torque shaft extending through one of said stub shafts and the sleeve extending through-the bulkhead and supporting an electric motor ixedly mounted on the end of the sleeve in outboard relationship with the speed reducer and on the Aother side of the bulkhead therefrom, whereby all lateral forces imposed on the pulley `druin are borne directly by the stub shafts, and said motor and speed reducer are self-aligning and wholly free of lateral strains.

3. In a motorized pulley, a load supporting frame comprising an exterior drum with end plates rigidly fixed thereto at each end thereof and hollow journal shafts xedly secured to the center portions of said end plates and projecting outwardly. in opposite directions whereby said frame of the pulley is adapted to be mounted for rotation in conventional bearings at each end of the drum; a transverse bulkhead between the ends of said drum, with a stationary internal driving unit consisting of an electric motor and a speed reducer within said drum and having a stationary torque shaft projecting therefrom at one end and a threaded sleeve projecting therefrom at the opposite end, with an electric motor threaded on said sleeve and supported solely thereby, with the armature shaft of the motor extending through said sleeve to the speed reducer and with said speed reducer being geared to said drumjsaid sleeve extending through and being supported by a -central bearing in said bulkhead; with the aforementioned torque shaft extending through one of the journal shafts and pulley bearings and secured to a torque arm having its outer end anchored to restrain the driving unit against rotation.

DANIEL A. SCHROCK;

REFERENCES CTED The following references are of record in the file of this patent:

UNITED STATES PATENTS therefromV 

